This invention relates to the acceleration of charged-particle beam and especially to the acceleration of high-current ion electron beams to higher velocities.
Conventional ion accelerators of either the linear or cyclotron type suffer from several disadvantages.
1. Being passive devices, the maximum accelerating fields they produce are limited.
2. To achieve relativistic ion energies, the conventional accelerators, because their maximum accelerating fields are limited, require either great length for linear devices or large radius for cyclotrons.
3. The currents must be small because the devices are inherently phase-unstable.
Of the proposed non-conventional accelerators using active media, there are two types.
1. The collective accelerator, such as the electron ring (ERA) or the moving electron well. The disadvantages of these is that they suffer from both instabilities and inertial effects.
2. The collective resonant accelerator, such as the autoresonant accelerator (ARA) which seeks to use an eigenmode of the active medium. This combines the best features of collective and conventional accelerators. The ARA suffers from the disadvantage of requiring a high-magnetic-field structure which is cumbersome and expensive and of producing an uncollimated beam at its output end.
The present invention is eonomical and compact compared to conventional accelerators. It can produce a high ion-beam current, the output beam being collimated. There is no need for a high magnetic field, and the efficiency of the device is relatively high.